(a) Field of the Invention
This invention generally relates to a double action, single lock snap hook. More particularly, but not by way of limitation, to a locking mechanism for a double action, self locking snap hook.
(b) Discussion of Known Art
The field of safety hooks which are used in fall prevention equipment presents several important problems which have yet to be solved by known devices. Safety hooks typically include a spring loaded gate which is used to close off the mouth of the hook in order to prevent the release or disengagement of rings, lines, or other accessories held in the mouth of the hook. The prevention of the unintended opening of the gate has been an important problem which has been addressed by a variety of mechanisms. Most mechanisms which are directed at preventing the unintended opening of the gate include a latch mechanism which prevents motion of the gate.
It is important that the latch mechanism not complicate the overall mechanism of the safety hook. It is known through experience that complicated mechanisms provide more opportunity for failure by way of failure of individual components, and particularly by way of failure due to damage of individual components while in use. Many known designs for closure mechanisms include complements that protrude from the profile of the hook mechanism, and thus are prone to mechanical damage from use in the field. Additionally, the exposure of the lock components provides easy access to these components, so that they may be modified, overridden, or even eliminated in the field by the user.
Additionally, it is desirable to provide a double action, self locking safety hook mechanism which can be activated by the user with a single hand. It is particularly desirable to provide a mechanism that can be activated by providing opposing forces by gripping the hook between the thumb and the index finger of the hand.
A review of known devices reveals that there remains a need for a safety hook closure mechanism which conceals important components to prevent damage in the field or modification by the user.
There remains a need for a safety hook closure mechanism which can be activated with a single hand, and which conceals or maintains important component during operation.
Still further, there remains a need for a safety hook which can be made from few parts, and particularly few parts requiring special forgings or castings. More specifically, there remains a need for a safety hook mechanism that uses stamped sheet metal components, and which uses the sheet metal components in a manner which avoids or minimizes the possibility of seizure of moving parts due to damage from use in the field.
There remains a need for a reliable closure mechanism which minimizes the effects of manufacturing tolerances on the function and reliability of the mechanism.